Mobile wireless communications devices, such as cellular telephones, typically have antennas that support communications in multiple operating frequency bands. Various types of antennas are used for mobile devices, such as helix, “inverted F”, folded dipole, and retractable antenna structures, for example. Helix and retractable antennas are typically deployed outside, i.e., on the exterior of, a mobile device (i.e., “exterior antennas”), and inverted F and folded dipole antennas are typically mounted within a mobile device case or housing (i.e., “internal antennas”).
Generally speaking, internal antennas are preferred over external antennas for mobile devices for mechanical and ergonomic reasons. Internal antennas are protected by the mobile device case or housing and therefore tend to be more durable than external antennas. External antennas may be cumbersome and make the mobile device difficult to use, particularly in limited-space environments. However, as mobile devices become smaller and thinner, it becomes increasingly more difficult to allocate sufficient surface area for an internal antenna so that it can be of an adequate size (i.e., electrical length) to provide desired operating characteristics.
One particularly advantageous antenna arrangement is set forth in U.S. Pat. No. 7,023,387 to Wen et al., which is assigned to the assignee of the present invention. This patent is directed to a multi-band antenna having a plurality of operating frequency bands. The antenna is mounted on a mounting structure, which may then advantageously be connected to a portion of a mobile wireless communications device, such as the housing. Thus, the antenna need not be located on the main printed circuit board (PCB), which may advantageously free up surface area on the PCB for other components and also allow for increased antenna surface area on the mounting structure.
While the foregoing system may provide desired antenna area and space savings in many mobile wireless communications devices, as device form factors continue to evolve it may be desirable to provide new antenna assemblies and configurations as well.